This invention relates to an apparatus for continuously forming and processing a glass-ceramic from raw materials.
Glass-ceramics are superior in mechanical strength and resistivity to heat to ordinary glasses and hence have been increasingly used for various parts of electrical and electronic machines and instruments and precision machines including optical and magnetic disk substrates, heat resistant and anti-corrosive parts, electronic parts.
For manufacturing a glass-ceramic, it is necessary to add a nucleating ingredient in raw materials. For ensuring the effect of adding such nucleating ingredient, a pre-melting processing such as culleting is generally performed before melting the raw materials. Melted glass is formed into blocks and thereafter is subjected to a heat treatment for crystallization.
FIGS. 8 and 9 show an example of a prior art process for manufacturing a glass-ceramic.
In these figures, glass materials which are melted in a melting apparatus 1 and reel ted glass is supplied to a glass forming mold 3 through a flow tube 2. The melted glass is formed by the mold 3 into a plate or a rod. The glass preform is then conveyed to an annealing kiln 4 where the glass preform is annealed to remove strain and homogenize the glass preform.
Then, the annealed glass preform is conveyed to a cutting device 5 where the glass preform is cut into blocks 6. Since a burr i s produced at end pot t ions of the blocks 6 as a result of cutting, the end portions of each block 6 are ground to remove the burr.
Thereafter, the blocks 6 are conveyed to a single furnace 7 where crystallization of the glass preform is performed. The blocks 6 which have completed the crystallizing process are conveyed to a subsequent processing device 8 where the thickness of the blocks 6 are adjusted by grinding and the blocks 6 are subjected to surface polishing to provide finished products.
In the above described prior art process for manufacturing a glass-ceramic, most processings are performed independently from one another. That is, the annealed glass preform is conveyed to the cutting device 5 which is located in a separate location from the annealing kiln 4 and the blocks 6 obtained by cutting the formed glass are conveyed to the single furnace 7 which is located in a separate location from the cutting device 6. It is therefore difficult in the prior art process to automatize the process for manufacturing a glass-ceramic to realize a large scale production. Besides, sufficient stability in the quality of the finished products is not guaranteed in the prior art process.
Furthermore, the cutting process by the cutting device 5 is made in such a manner that a block produced by cutting has a larger size than a final finished glass-ceramic product and, therefore, the process after crystallization for processing the crystallized block 6 to the final finished product requires a considerable labor and time which results in a high manufacturing cost.
It is, therefore, an object of the invention to provide an apparatus for continuously forming and processing a glass-ceramic which is capable of directly forming a melted glass into a glass preform of a predetermined form which is ready for the crystallizing process and performing the subsequent crystallizing process continuously.